if the gravity readings are changing or the airlock is bubbling, i'd just step away and let it ferment. i got a vinegary taste for the first week after bottling with my very first batch; i think it was because i didn't let it ferment out all the way. cider fermentation smells terrible, but the yeast cleans up after itself if you give it time. i wouldn't even worry for two more weeks. then bottle it, let it sit for a two weeks or more, then drink it.